1. Uncontrolled before‐and‐after studies.

Study	Objectives	Study design	Study population	Intervention	Outcomes measured	Key results
Apsler et al., 2003 (USA).	To increase booster seat use among low‐income parents.	Uncontrolled pretest/posttest. Used focus groups, surveys, and observation.	Low‐income parents with children 4 to 8 years old enrolled in nine day care centers in Providence, Rhode Island.	Three‐level intervention. 1. Education: trained day care staff and parents about risks of not using booster seats and distributed pamphlets in multiple languages. 2. Policy: day care center policies changed to recommend use of booster seats. 3. Incentive: gift certificate to local grocery store. All families were given free booster seats. Follow‐up done 4 to 8 weeks after baseline.	Percentage of children 4 to 8 years old seen riding in booster seats.	Booster seat use All ages; pre 3%, post 38%. Age 4‐5; pre 5%, post 63%. Age 6; pre 2%, post 19%. Age 7‐8; pre 0%, post 0%. No restraint All ages; pre 56%, post 26%. Age 4‐5; pre 54%, post 13%. Age 6; pre 57%, post 36%. Age 7‐8; pre 59%, post 46%. Changes were significant at P<0.01. 1. Substantial increase in booster seat use after intervention. 2. Booster seat use decreased with age. 3. No differences between levels of intervention and use of booster seats.
Browning et al., 1999 (Australia)	To increase appropriate child car restraint use among 4 to 6 year old rural schoolchildren.	Uncontrolled pretest/posttest. Used observation, self‐report, and Questionnaire.	Rural schoolchildren 4 to 7 years old enrolled in kindergarten, pre‐primary or year 1 in five schools in Brunswick, Harvey, and Yarloop, Australia, and the children's parents.	School‐based intervention. Parents received educational materials, vouchers for free booster seats for eligible families, free checking of child restraints. Children received rewards in school for reporting restraint use. Follow‐up done 3 months after baseline.	Observed use of child restraints. Percentage of children 4 to 6 years old seen using age‐appropriate restraints Parents' attitudes. Percentage of parents using offer of free child restraints check.	Overall child restraint Pre 79%, post 90% (P=0.002). Age‐appropriate restraint Pre 45%, post 69% (P<0.0009). 40% thought child restraints were too expensive. 85% believed not everyone can tell if a child restraint is properly installed. Despite 85% of parents believing not everyone could tell if a child restraint is properly installed, less than 3% used the free checking of child restraints.
Cooper at al., 2004 (USA)	To evaluate the impact of the Child Passenger Safety Initiative on parents' knowledge, use, and misuse of child safety seats.	Uncontrolled pretest/posttest. Used interviews and observation. Quasi‐experimental.	Families with children aged 0 to 6 belonging to vulnerable groups (minorities, low‐income) and attending seven public hospitals and health systems in California.	Child Passenger Safety Initiative. Education of parents/caregivers on proper child restraints, distribution of free and low‐cost seats, trained physicians/nurses to teach patients about proper car seat use, outreach component educated foster parents and child welfare workers about child passenger safety. Follow‐up done approximately 1 year after baseline.	Knowledge of booster seat safety law. Reported use of booster seats for children aged 4 to 6. Observed use of booster seats.	Drivers with a knowledge of child passenger safety law; Pre 79.4%, post 74.6% (P<0.05). Drivers who reported always using booster seats; Pre 57.3%, post 55.5%. Observed booster seat use decreased between pre‐ and posttest (P<0.05) [no data reported].
Decina et al., 1994 (USA)	To evaluate the effect of locally funded education and enforcement programs aimed at increasing child restraint use. To increase proper child restraint use.	Pretest/posttest with control group. Used observation and self‐report.	Target: Residents of Tredyffrin and Haverford, Pennsylvania. Control: Residents of Abington, Pennsylvania.	One year educational and enforcement intervention. Included kickoff events, distribution of print materials and promotional items through community, school visits, and citations.	Percentage of toddlers 3 to 5 years old observed using child restraint. Percentage of "fully protected" toddlers.	Child restraint use in toddlers aged 3 to 5: Tredyffrin; pre 40.6%, post 49.4%. Haverford; pre 30.5%, post 39.4%. Abington; pre 38.7%, post 38.6%. "Fully protected" toddlers aged 3 to 5: Tredyffrin; pre 36.5%, post 45.1%. Haverford; pre 27%, post 37.5%. Abington; pre 33.2%, 33.6%. These findings were not statistically significant
Griffin, 2003 (USA)	To conduct community‐based interventions to increase booster seat use. To develop an observational survey to collect accurate booster seat data. To assess the effectiveness of the interventions.	Pretest/posttest; observation; interview.	Target: Children aged 4 to 7 in California. Control: None.	Give Kids a Boost! Community‐based assessments of resources; checkup events; mass media and educational print materials; free and low‐cost booster seat programs. Follow‐up done 1 year after baseline.	Percentage of children aged 4 to 7 observed riding in booster seats.	Booster seat use; Pre 26%, post 53%.
Foss, 1989 (USA)	To assess the impact of a community‐wide incentive campaign on seat belt use.	Pretest/posttest; telephone survey; observation.	Target: Children aged 0 to 12. Control: None.	Five month incentive campaign aimed at parents and children; radio spots; flyers.	Percentage of children aged 0 to 12 observed using seat belts.	Observed seat belt use: Age 0‐5; pre 26.8%, post 36.4%. Age 6‐12; pre 10.4%, post 11.9%. Findings showed short‐term improvements in seat belt use in response to radio spots
Murrin, 2004 (USA)	To compare before‐law and after‐law use of booster seats in California.	Uncontrolled pretest/posttest (before and after law). Used data gathered during child restraint inspection events. Cross‐sectional.	Children up to age six or weighing less than 60 pounds.	Enactment of California law requiring children under age six, or less than 60 pounds to ride in a booster seat.	Percentage of all seats inspected that were boosters.	Booster seat inspections; Pre 5.6%, 11%. Proportion of booster seats being inspected increased after passage of law.
Hemmo‐Lotem, 2004 (Israel)	To evaluate parents' knowledge and attitudes about child passenger and booster seat use for children 4 to 9 years old. To evaluate an intervention program initiated by BETEREM. To identify groups and factors that influence booster seat use.	Uncontrolled pretest/posttest. Used telephone surveys.	Parents with children under 15, including Russian‐speaking subset.	Enforcement component, media campaign; details not provided.	Awareness of what a booster seat is. Ability to provide correct details regarding nature and use of booster seats.	Awareness; Pre 38%, post 44%. Providing correct details Pre, 32%, post 39%. Russian‐speaking parents knew less about booster seat use than other parents. 57% of parents of children aged 4 to 9 were unaware of the requirement that their children should use booster seats.
Philbrook et al., 2005 (USA)	To test the effectiveness of three school‐based booster seat intervention methods to increase booster seat use in a public school system. To determine the feasibility of three school‐based interventions. To determine differences in attitudes and behaviors in the different intervention groups.	Uncontrolled pretest/posttest. Used surveys.	Children in kindergarten in three public school systems in Minneapolis, Minnesota, and their parents.	Three school‐based intervention groups. Group 1: information on booster seats for parents sent home with children. Group 2: parent classes (in Spanish and English), videos, free booster seats. Group 3: kindergarten presentation on booster seat use and literature sent home to parents. All parents who participated in evaluation received free booster seat. Follow‐up done 3 and 6 months after intervention.	Booster seat use.	Booster seat use: Group 1; pre 50%, post 42%. Group 2; pre 16%, post 39%. Group 3; pre 30%, post 55% Increase for Group 2 was significant (P=0.011). Increase for Group 3 was significant (P=0.025). Solely sending information home to parents was not an effective means of increasing booster seat use.
Pless et al., 1986 (Canada)	To assess the impact of a media campaign on use of child restraints in Montreal.	Uncontrolled pretest/posttest (before and after campaign). Used observation.	Parents with young children in four areas of Montreal.	Media campaign aimed at parents in English and French. Discussions of campaign on television and radio shows, pamphlets and posters placed in health settings and retail stores. Follow‐up done six months after baseline.	Percent of children aged 0 to 12 years seen properly restrained.	Properly restrained: Age 5‐11; pre 7.2%, post 8.6%. Increases were not significant for children aged 5‐11 years. Greater increases seen at sites with higher proportions of English‐speakers.
Rock, 1996 (USA)	To assess the impact of the 1983 Illinois child restraint law.	Pretest/posttest; ARIMA techniques (autoregressive integrated moving average).	Target: Children aged 0‐9. Control: None.	Enactment of law requiring children under age 4 to ride in approved safety seat and children aged 4 to 5 to ride in safety seat or use seat belt.	Fatalities and injuries among children aged 0 to 9.	Aged 0‐4: Law resulted in 10% decrease in number killed or injured, 17% decrease in rate injured per accident, and 14% decrease in percentage of all fatalities and injuries. Age 5‐9: No significant reductions.
Sheese, 1998 (USA)	To increase use of child safety seats among children 3 to 4 years old.	Pretest/posttest (before and after campaign); survey; observation.	Target: Children aged 3 to 4 in Indiana. Control: None.	Statewide media campaign aimed at parents and children; included visits to kindergarten classes.	Percentage of children aged 3 to 4 observed using any child restraint.	Any child restraint; Pre 25%, post 41%.